Usually the data transfer networks comprise terminal devices, servers, routers, and various data switches connected to the transfer channel. The terminal devices are usually intended for receiving information from the network and for presenting it to the user and/or for transmitting the data inputted by the user to the terminal device to the network. The servers are usually used for storing data and/or for processing it. The purpose of the routers is to transmit further the data received from a terminal device or from a server to an upper level router and/or transmit further the data received from an upper level router to a server or to a terminal device. The terminal devices can be connected directly to the servers or the connection is made by using a local area network. The transfer channel between two terminal devices in a data transfer network comprises different wired and wireless transfer channels connected to each other by means of servers, routers, and data switches.
Usually the network is formed to a star or a tree in such a way that the terminal devices are in connection with each other by means of a local area network, servers, and routers. The network can also be formed of star-like parts connected to each other. The connections from one terminal device to another are usually formed by means of servers and routers. Usually the users take a connection with their terminal devices to the server of the service provider by means of the network and the devices thereof The forming of the connection even between two neighboring terminal devices has to be done usually through the server of the service provider, because the service is available generally only on the server of the service provider. This leads easily to the congestion of the network and therefore to the lengthening of the response times. To reduce this disadvantage e.g. in the Internet the so-called proxy-servers are used especially for storing the data used often or most recently. In the terminal devices the corresponding data can be stored in its own intermediate memory. The data stored in this way has not, however, the same content as the corresponding data retrieved from the server and therefore the terminal devices and the servers have to be controlled in such a way that they update the stored data every now and then.
It is characterizing to the known networks also that the servers, routers, and data switches used in them are each dedicated and suitable for performing generally only one for them characteristic function in the network. Further it is characterizing to the known networks that they are controlled and their function is monitored centrally from certain connections dedicated to the control or monitoring.